feat(search): fall back to keyless Photon geocoding

Place search was Google-only: searchAndFlyTo threw without a key, and with a
key whose Geocoding API is not enabled it returned nothing. Both cases leave
the LOCATION box and the fly_to_location voice tool unable to resolve a name,
even though every other layer in the app works keyless.

src/keylessGeocoder.js adapts Photon (komoot, over OpenStreetMap) into the
shape the Google path already produces — lat/lng, label, Google-style types,
{southwest,northeast} bounds — so geocodeNavigationMode, regionFramingPlan and
the region-swath cap keep running on unchanged inputs. The translation lives at
the boundary and nowhere else; Google remains primary and its branch is
unchanged when it answers.

Detection is the empty result, not an exception: an unenabled Geocoding API
answers HTTP 200 with REQUEST_DENIED. Places near-view recovery is now
attempted only when a key exists, since Places is a Google service too.

Three translations are load-bearing, and each was found by querying the live
service rather than by reasoning about OSM tagging:

- Google's `bounds` PREFERS results inside the box; Photon's `bbox` FILTERS to
  it. Sent as a bbox, searching "Ho Guom, Ha Noi" while looking at Austin
  returns features: []. Sent as Photon's lat/lon proximity bias it finds the
  lake, and "Sixth Street" still resolves to Austin's over Austin and to
  England's over London.
- Photon's `extent` is [west, north, east, south]. Read as [w,s,e,n] it yields
  an inverted but finite box that frames the camera at nothing.
- A specific OSM key=value rule must beat the coarse `type`. Photon tags a lake
  `water=lake` with `type: 'other'` — unmapped, that framed Hoan Kiem Lake as a
  precise place and put the camera 26 m over the water — and tags a town square
  `type: 'locality'`, which framed Times Square as if it were a city.

searchAndFlyTo no longer throws when no key is present. Both callers already
read a null return as not-found (ui.js renders its miss branch, gevActions
reports ok: false), so the removed throw has no consumer.

Verified end to end through the real search box, with a key Google refuses:
one denied Google geocode, one Photon request, camera from Austin
(30.2700, -97.7400) to 21.0288, 105.8524 — Hoan Kiem Lake to within metres —
and "Ha Noi" framed at province scale. npm test 2604/2604; npm run build
clean; npm run test:track 97/3, the same three failures unmodified main
produces on this machine.

docs/CURRENT-STATE.md

@@ -2181,6 +2181,12 @@ silently demoting every later lookup for the session.
 - Input is the live basemap label context (place/street/nearby-place labels + enabled layers) — the model is instructed not to infer from coordinates.
 - Output is sanitized to exactly five words; falls back to the deterministic telemetry summary on error/timeout (5s abort); typewriter animation on update.
 
+### Keyless place search (August 2026)
+
+- `src/keylessGeocoder.js` is a Photon (komoot/OpenStreetMap) adapter used by `searchAndFlyTo` when the Google geocode produces no result: no key configured, or a key whose Geocoding API is not enabled — Google answers HTTP 200 with `REQUEST_DENIED`, so the empty result is the detector, not an error. Google stays the primary path and is byte-unchanged when it answers, and the Places near-view recovery is only attempted when a key exists, since Places is a Google service.
+- The adapter normalizes into the shape the Google path already produces — `lat`/`lng`, label, Google-style `types`, `{southwest,northeast}` bounds — so `geocodeNavigationMode`, `regionFramingPlan` and the region-swath cap keep running unchanged. Two translations are load-bearing and are pinned by tests: Photon's `extent` is `[west, north, east, south]`, and a specific OSM `key=value` rule beats the coarse `type` (Photon reports a lake as `water=lake` with `type: 'other'`, which framed at building range put the camera 26 m over the water; it reports a town square as `type: 'locality'`, which framed a plaza as a city).
+- The shared `viewportBias()` string is sent as Photon's `lat`/`lon` PROXIMITY bias, never as `bbox`: Google's `bounds` prefers, Photon's `bbox` filters, and the literal translation makes every off-screen search return nothing. One result per query, memoized by query+bias (misses included) to respect komoot's fair use.
+
 ### Map Stack Switcher (June 2026)
 
 - `src/mapStackController.js` switches between Google Photorealistic 3D (`photoreal`, the default when a Google or ion key is present), keyless Esri World Imagery (the zero-key default landing, with keyless terrain), Bing Aerial / Aerial-with-Labels via Cesium ion world imagery (require `CESIUM_ION_TOKEN`), and OSM tile fallback. Bing Road is **retired**: it is gone from `MAP_STACKS`, from the `set_map_stack` enum, and from the voice aliases (road phrasings now resolve to OSM, the one shipped road basemap). An old `map=bing-road` link is simply an unknown id and takes `setStack()`'s existing photoreal fallback with the Google 3D tile lit — pinned live in `scripts/qa-map-source-tray.mjs`.